Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/18—Diffraction gratings
  • G02B5/1847—Manufacturing methods
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0081—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for altering, e.g. enlarging, the entrance or exit pupil
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/01—Head-up displays
  • G02B27/017—Head mounted
  • G02B27/0172—Head mounted characterised by optical features
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
  • G02B27/4272—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having plural diffractive elements positioned sequentially along the optical path
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/02—Optical fibres with cladding with or without a coating
  • G02B6/02033—Core or cladding made from organic material, e.g. polymeric material
  • G02B6/02038—Core or cladding made from organic material, e.g. polymeric material with core or cladding having graded refractive index
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/26—Optical coupling means
  • G02B6/34—Optical coupling means utilising prism or grating
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
  • G02B6/4201—Packages, e.g. shape, construction, internal or external details
  • G02B6/4256—Details of housings
  • G02B6/4257—Details of housings having a supporting carrier or a mounting substrate or a mounting plate
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/01—Head-up displays
  • G02B27/017—Head mounted
  • G02B27/0172—Head mounted characterised by optical features
  • G02B2027/0174—Head mounted characterised by optical features holographic
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B2207/00—Coding scheme for general features or characteristics of optical elements and systems of subclass G02B, but not including elements and systems which would be classified in G02B6/00 and subgroups
  • G02B2207/101—Nanooptics

Definitions

• Embodiments of the present disclosure generally relate to optical device fabrication. Specifically, embodiments of the present disclosure relate to optical device fabrication using methods of discrete grating assembly and optical interconnection.
• VR virtual reality
• HMD head-mounted display
• glasses or other wearable display devices that have near-eye display panels as lenses to display a VR environment that replaces an actual environment.
• Augmented reality enables an experience in which a user can still see through the display lenses of the glasses or other HMD device to view the surrounding environment, yet also see images of virtual objects that are generated for display and appear as part of the environment.
• AR can include any type of input, such as audio and haptic inputs, as well as virtual images, graphics, and video that enhances or augments the environment that the user experiences.
• a virtual image is overlaid on an ambient environment, with the overlaying performed by optical devices.
• an optical device in one embodiment, includes an optical device substrate, a portion of a first donor substrate disposed on an upper surface of the optical device substrate and a first grating disposed on the portion of the first donor substrate.
• the first grating includes a first plurality of optical device structures.
• the optical device further includes a portion of a second donor substrate disposed on the upper surface of the optical device substrate and a second grating disposed on the portion of the second donor substrate.
• the second grating includes a second plurality of optical device structures and an inkjet material disposed between the first grating and the second grating.
• the inkjet material includes an inkjet height planar with or greater than a height of the first plurality of optical device structures and the second plurality of optical device structures.
• an optical device in another embodiment, includes an optical device substrate having a first refractive index, and a portion of a first donor substrate disposed on an upper surface of the optical device substrate.
• the first donor substrate has a second refractive index.
• the optical device further includes a first grating disposed on the portion of the first donor substrate.
• the first grating includes a first plurality of optical device structures.
• the optical device further includes a portion of a second donor substrate disposed on the upper surface of the optical device substrate.
• the portion of the second donor substrate includes a third refractive index.
• the optical device further includes a second grating disposed on the portion of the second donor substrate, the second grating including a second plurality of optical device structures.
• the optical device further includes an inkjet material disposed between the first grating and the second grating.
• the inkjet material has an inkjet refractive index, with the inkjet refractive index, the first refractive index, the second refractive index, and the third refractive index being substantially equal.
• a method of forming an optical device includes forming input coupling gratings on a first donor substrate, forming output coupling gratings on a second donor substrate, and trimming each of the first donor substrate and the second donor substrate to a donor substrate height.
• the method further includes dicing each input coupling grating and each output coupling grating into a portion of the first donor substrate and a portion of the second donor substrate, adhering the portion of the first donor substrate and the portion of the second donor substrate to an upper surface of an optical device substrate, and disposing an inkjet material between the input coupling grating and the output coupling grating on the optical device substrate.
• Figure 1 is a schematic, top view of an optical device according to embodiments described herein.
• Figures 2A-2C are schematic, top views of a donor substrate according to embodiments described herein.
• Figure 3 is a flow diagram of a method of forming the optical device as shown in Figures 4A-4F according to embodiments described herein.
• Figures 4A-4F are schematic, side views of the formation of the optical device during the method according to embodiments described herein.
• Embodiments of the present disclosure generally relate to optical device fabrication. Specifically, embodiments of the present disclosure relate to optical device fabrication using methods of discrete grating assembly and optical interconnection.
• Figure 1 is a schematic, top view of an optical device 100.
• the optical device 100 described below is an exemplary optical device.
• the optical device 100 is a waveguide combiner, such as an augmented reality waveguide combiner.
• the optical device 100 may additionally be an optical device utilized for optical sensing (e.g., eye tracking capabilities).
• the optical device 100 is a flat optical device, such as metasurface.
• the optical device 100 includes a plurality of optical device structures 102.
• the optical device structures 102 are disposed on portions 105 of a donor substrate 115 (shown in Figure 2).
• the device structures 102 may be nanostructures having sub-micron dimensions, e.g., nano-sized dimensions.
• a critical dimension 106 of the optical device structures 102 has sub-micron dimensions.
• the critical dimension 106 is less than 2 micrometers (pm).
• the critical dimensions 106 are about 100 nanometers (nm) to about 1000 nm.
• regions of the device structures 102 correspond to one or more gratings 104, such as a first grating 104A, a second grating 104B, and a third grating 104C.
• the first grating 104A corresponds to an input coupling grating.
• the second grating 104B corresponds to an intermediate grating.
• the third grating 104C corresponds to an output coupling grating.
• Each of the gratings 104 is disposed on the respective portions 105 of the donor substrate 115 (shown in Figure 2).
• Each portion 105 is disposed on an upper surface 103 of the optical device substrate 101 .
• the cross-sections of the optical device structures 102 have different shaped cross-sections. In other embodiments, which can be combined with other embodiments described herein, the cross-sections of the optical device structures 102 of the optical device 100 have cross-sections with substantially the same shape. In some embodiments, which can be combined with other embodiments described herein, at least one of the critical dimensions 106 of an optical device structure 102 may be different from the other critical dimensions 106 of the optical device structures 102. In other embodiments, which can be combined with other embodiments described herein, the critical dimensions 106 of the optical device structure 102 are the same.
• the structure material of the optical device structures 102 includes non-conductive materials, such as dielectric materials.
• the dielectric materials may include amorphous, polycrystalline, or crystalline materials.
• Examples of the dielectric materials include, but are not limited to, silicon-containing materials, such as Si, silicon nitride (SisN4), silicon oxynitride, silicon carbide (SiC), silicon carbon nitride (SiCN), silicon dioxide, fused silica, or quartz.
• the silicon may be crystalline silicon, polycrystalline silicon, or amorphous silicon (a-Si).
• the structure material of the optical device structures 102 includes, but is not limited to, titanium dioxide (TiC ), zinc oxide (ZnO), tin dioxide (SnC ), aluminum-doped zinc oxide (AZO), fluorinedoped tin oxide (FTO), cadmium stannate (Cd2SnO4), cadmium stannate (tin oxide) (CTO), zinc stannate (SnZnOs), tantalum oxide (Ta2Os), vanadium (IV) oxide (VOx), or niobium oxide (Nb20s) containing materials.
• the material of the optical device structures 102 includes nanoimprint resist materials.
• nanoimprint resist materials include, but are not limited to, at least one of spin on glass (SOG), flowable SOG, organic, inorganic, and hybrid (organic and inorganic) nanoimprintable materials that may contain at least one of silicon oxycarbide (SiOC), TiO2, silicon dioxide (SiO2), vanadium (IV) oxide (VOx), aluminum oxide (AI2O3), indium tin oxide (ITO), ZnO, tantalum oxide (Ta2Os), silicon nitride (SisN4), titanium nitride (TiN), zirconium dioxide (ZrO2) containing materials, or combinations thereof.
• the optical device substrate 101 and the donor substrate 115 may be formed from materials including, but not limited to, silicon (Si), silicon dioxide (SiO2), fused silica, quartz, silicon carbide (SiC), germanium (Ge), silicon germanium (SiGe), indium phosphide (InP), gallium arsenide (GaAs), diamond, gallium nitride (GaN), gallium oxide (Ga2Os), or sapphire containing materials.
• the optical device substrate 101 and the donor substrate 115 include high refractive index glasses, consisting of one or more of: silicon dioxide (SiC>2), boron oxide (B2O3), titanium oxide (TiO2), zirconium dioxide (ZrC ), tantalum oxide (Ta2Os), niobium oxide (Nb20s), lanthanum oxide (La20s), bismuth oxide (Bi20s), zinc oxide (ZnO), lead oxide (PbO), lithium oxide (l_i2O), sodium oxide(Na2O), potassium oxide (K2O), magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), aluminum oxide (AI2O3) and gallium oxide (Ga2Os).
• the material of the optical device substrate 101 and the donor substrate 115 may be different.
• the optical device substrate 101 has a first refractive index of about 1.6 to about 3.0.
• the donor substrate 115 has a second refractive index of about 1 .6 to about 3.0.
• an inkjet material 108 is disposed between the plurality of gratings 104.
• the inkjet material 108 is a flowable material that can be deposited onto selective areas on the optical device substrate 101 and the donor substrate 115 using inkjet printing.
• the inkjet material 108 may be further crosslinked or cured after printing to yield a solidified film.
• the inkjet material 108 is tuned to have an inkjet refractive index close or identical to a refractive index of the optical device structures 102.
• the ink to yield the inkjet material 108 is a colloidal dispersion of nanoparticles.
• the nanoparticles can include one or more of titanium oxide (TiC>2), zirconium dioxide (ZrC ), tantalum oxide (Ta2Os), niobium oxide (Nb20s), lanthanum oxide (La2Os), bismuth oxide (Bi20s), or zinc oxide (ZnO).
• the ink is derived from metal oxide precursors, including but not limited to, metal alkoxides, metal acetates and metal nitrates.
• the ink formulation may also contain the following components: solvents such as water, ethanol, propylene glycol methyl ether, cyclopentanone; acid and bases such as acetic acid, hydrochloric acid, citric acid, sodium hydroxide, ethanolamine; crosslinkers, monomers and polymers such as triethylene glycol dimethacrylate, 9-vinyl carbazole, polyimides, and polyphosphonates.
• solvents such as water, ethanol, propylene glycol methyl ether, cyclopentanone
• acid and bases such as acetic acid, hydrochloric acid, citric acid, sodium hydroxide, ethanolamine
• crosslinkers, monomers and polymers such as triethylene glycol dimethacrylate, 9-vinyl carbazole, polyimides, and polyphosphonates.
• the inkjet material 108 after curing has an inkjet refractive index of between about 1.6 and about 3.0.
• the refractive index of the optical device structures 102 is also between about
• FIGS 2A-2C are schematic, top views of a donor substrate 115.
• Each donor substrate 115 includes a plurality of gratings 104.
• Each grating 104 includes the plurality of optical device structures 102 (shown in detail in Figure 1 ).
• the plurality of gratings 104A-C are each fabricated on a separate donor substrate 115 to allow dense packing of gratings 104.
• the plurality of gratings 104 are not limited to a rectangular shape as shown in Figures 2A-2C.
• Figure 2A includes a first configuration 200A of the donor substrate 115.
• the first configuration 200A includes the plurality of first gratings 104A formed on the donor substrate 115.
• Each of the plurality of first gratings 104A corresponds to an input coupling grating.
• Each donor substrate 115 may hold between 4 and 3000 first gratings 104A depending on the size of the donor substrate 115.
• the donor substrate 115 may include about 160 of the first gratings 104A.
• the plurality of the first gratings 104A may be formed on the donor substrate 115 as needed to maximize the number of the first gratings 104A on the donor substrate 115.
• Figure 2B includes a second configuration 200B of the donor substrate 115.
• the second configuration 200B includes the plurality of second gratings 104B formed on the donor substrate 115.
• Each of the plurality of second gratings 104B corresponds to an intermediate grating.
• Each donor substrate 115 may hold between 4 and 300 second gratings 104B depending on the size of the donor substrate 115.
• the donor substrate 115 may include about 32 of the second gratings 104B.
• the plurality of the second gratings 104B may be formed on the donor substrate 115 as needed to increase or maximize the number of the second gratings 104B on the donor substrate 115.
• Figure 2C includes a third configuration 200C of the donor substrate 115.
• the third configuration 200C includes the plurality of third gratings 104C formed on the donor substrate 115.
• Each of the plurality of third gratings 104C corresponds to an output grating.
• Each donor substrate 115 may hold between 4 and 300 third gratings 104C depending on the size of the donor substrate 115.
• the donor substrate 115 may include about 24 of the third gratings 104C.
• the plurality of the third gratings 104C may be formed on the donor substrate 115 as needed to maximize the number of the third gratings 104C on the donor substrate 115.
• Forming the first gratings 104A, the second gratings 104B, and the third gratings 104C on distinct donor substrates 115 allows for the utilization of more surface area of the donor substrate 115. As described below in method 300, forming the first gratings 104A, the second gratings 104B, and the third gratings 104C on distinct donor substrates 115 will decrease cost of optical device fabrication by utilizing more surface area of the donor substrates 115. Additionally, the fabrication of the first gratings 104A, the second gratings 104B, and the third gratings 104C each may employ different fabrication operations. Thus, fabrication costs may be further reduced by forming the respective gratings separately such that each donor substrate 115 may be subject to the same fabrication process.
• FIG 3 is a flow diagram of a method 300 of forming the optical device 100 as shown in Figures 4A-4F.
• Figures 4A-4F are schematic, side views of the formation of the optical device 100 during the method 300.
• the method 300 and the Figures 4A-4F depict the optical device 100 with the first gratings 104A (e.g., the input coupling grating) and the third gratings 104C (e.g., the output coupling grating), however, the method 300 contemplates the formation of the optical device 100 with the second gratings 104B (e.g., the intermediate grating) as well.
• the optical device structures 102 of each grating 104 are formed at the same height 402, it is contemplated that the height 402 of each of the optical device structures 102 may vary across the donor substrate 115.
• a plurality of gratings 104 are patterned on a donor substrate 115.
• Figure 4A only shows the first gratings 104A being formed on the donor substrate 115, the second gratings 104B and/or the third gratings 104C are formed on different donor substrates 115.
• the plurality of gratings 104 of each donor substrate 115 are substantially identical. It is contemplated that the method 300 described herein is not limited to one grating type on one donor substrate 115. It is contemplated to design and fabricate different gratings on the same donor substrate 115 to further utilize the blank area of each respective donor substrate 115.
• operations 301 -303 will be described with reference to the first gratings 104A. However, the operations 301 -303 may also be performed with the second gratings 104B and the third gratings 104C. Although only three of the first gratings 104A are shown in Figure 4A, it is contemplated that any number of the gratings 104 may be formed on the donor substrate 115.
• the donor substrate 115 is trimmed.
• the donor substrate 115 is trimmed to a donor substrate height 408.
• the donor substrate height 408 is determined based on a predetermined substrate thickness 412 (shown in Figures 4E and 4F).
• the predetermined substrate thickness 412 is the summation of the donor substrate height 408 and an optical device substrate height 410.
• the donor substrate 115 is trimmed such that when positioned on the optical device substrate 101 , the predetermined substrate thickness 412 is achieved.
• the desired substrate thickness 412 is 800 pm
• the optical device substrate height 410 is 500 pm
• the donor substrate height 408 would be about 300 pm.
• each grating 104 (e.g., each first grating 104A shown in Figure 4C) is diced into a portion 105 of the donor substrate 115.
• the portions 105 are diced with a substrate dicing process such as laser ablation cutting, filamentation, diamond blade cutting, or using a precision dicing saw.
• the portion 105 of the donor substrate 115 with the first grating 104A and the portion 105 of the donor substrate 115 with the third grating 104C are positioned proximate an optical device substrate 101.
• the portion 105 of the donor substrate 115 with the second grating 104B (not shown) are bonded to the optical device substrate 101.
• alignment marks are designed and fabricated on the optical device substrate 101 and the donor substrate 115. The alignment marks can be complementary in shape, or the position of each mark can be read by an alignment system to calculate and align the relative positions of the optical device substrate 101 and the donor substrate 115.
• the plurality of optical device structures 102 of the first grating 104A are perpendicular relative to the surface 202 of the donor substrate 115 and the upper surface 103 of the optical device substrate 101 .
• the plurality of optical device structures 102 of the third grating 104C are angled relative to the surface 202 of the donor substrate 115 and the upper surface 103 of the optical device substrate 101 .
• Each of the gratings 104 may be angled or perpendicular relative to the surface 202.
• the portion 105 of the donor substrate 115 with the first grating 104A is adhered to an optical device substrate 101 . Further, the portion 105 of the donor substrate 115 with the third grating 104C is adhered to the optical device substrate 101. In some embodiments, the portion 105 of the donor substrate 115 with the second grating 104B (not shown) are bonded to the optical device substrate 101 .
• the multiple portions 105 of the donor substrate 115 adhere to the optical device substrate by bonding to the portions 105, using a process such as adhesive bonding, glass frit bonding, or fusion bonding. Fusion bonding refers to spontaneous adhesion of two planar substrates without the addition of any intermediate layer. In fusion bonding, a plasma pretreatment can be used to generate a clean surface free from organic contamination.
• an inkjet material 108 is disposed on the optical device substrate 101 to form the optical device 100.
• the inkjet material 108 is disposed to be in between the optical device structures 102 of each grating 104.
• the inkjet material 108 is also disposed to be between each adjacent donor substrate 115.
• the inkjet material 108 is disposed via an inkjet printing process.
• the inkjet material 108 is disposed with an inkjet height 404.
• the inkjet height 404 is in plane or higher with a top surface 406 of the optical device structures 102.
• the inkjet refractive index is substantially equal to a first refractive index of the optical device substrate 101 and a second refractive index of the donor substrate 115.
• the inkjet material 108 optically interconnects the first grating 104A to the third grating 104C such that the optical path of incident light on the optical device 100 allows for total internal reflection.
• the inkjet refractive index is substantially equal to a first refractive index of the optical device substrate 101 and a second refractive index of the donor substrate 115, light is able to propagate through the optical device 100.
• the inkjet material 108 does not require extra patterning operations to define the area of interconnection between the gratings 104.
• optical device fabrication using methods of discrete grating assembly and optical interconnection are provided herein.
• discrete gratings corresponding to one of an input coupling grating, an intermediate grating, or an output coupling grating of an optical device are formed on separated donor substrates.
• the donor substrates are diced into individual gratings and adhered to an optical device substrate.
• An inkjet material is disposed between the gratings to optically interconnect the portions of the optical device.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Optical Couplings Of Light Guides (AREA)
• Optical Integrated Circuits (AREA)
• Diffracting Gratings Or Hologram Optical Elements (AREA)

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• 2023
  • 2023-03-14 EP EP23775469.2A patent/EP4500239A4/de active Pending
  • 2023-03-14 US US18/183,273 patent/US20230305203A1/en active Pending
  • 2023-03-14 KR KR1020247035195A patent/KR20240163151A/ko active Pending
  • 2023-03-14 CN CN202380027999.6A patent/CN118891548A/zh active Pending
  • 2023-03-14 WO PCT/US2023/015184 patent/WO2023183162A1/en not_active Ceased
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